1. Field of the Invention
This invention relates to corrosion inhibition in well-drilling operations. More particularly it relates to methods of corrosion inhibition using amine salts of certain polycarboxylic acids and certain monoamines in aqueous well-packer solutions and aqueous drilling fluids.
2. Prior Art
It is known to treat aqueous systems, such as drilling muds with corrosion inhibitors to prevent unwanted corrosion of metal equipment during well-drilling operations. Surfactant systems such as succinamates have also been disclosed to be useful in recovering oil from subterranean reservoirs. See, for example, U.S. Pat. No. 4,120,800 to Valcho et al.
The use of ammonium carboxylates as corrosion inhibitors in several contexts has been described in several patents. For example: U.S. Pat. No. 4,113,498 discloses corrosion inhibitors comprising a reaction product of an aliphatic carboxylic acid, a polyhydroxy carboxylic acid and an alkanol amine.
U.S. Pat. No. 4,053,426 and British Pat. Specification No. 1,532,836 describe water-based, metal working fluids containing amine salts of a partial ester of an alkenyl or alkyl succinic acid.
Japanese Patent Application 156,684, as abstracted in Derwent publications abstract number 59567A/33*j5 3079-738, discloses water-soluble corrosion inhibitors for steel containing a carboxylic acid and an amino alcohol.
U.S. Pat. No. 2,726,215 discloses alkali and alkaline earth metal salts of dicarboxylic acids and their use in aqueous systems as corrosion inhibitors.
U.S. Pat. No. 2,638,449 discloses reaction products of fatty acids and dialkanol amines which are further reacted with alkenyl succinic acids having substituents of up to 31 carbon atoms.
U.K. Patent application 1,521,984, as abstracted in Derwent publications, abstract number J5014W-52, describes detergents made by reacting adipic or sebacic acid with mono-, di- or tri-ethanol amine and adjusting the pH of the reaction product to 7-7.5 with amine. The product is described as being soluble in water.
U.S. Pat. No. 4,120,665 describes water-soluble complex salts of certain metals, hydroxycarboxylic acids and phosphoric esters of alkanol amines and their use as corrosion inhibitors.